adaptive immune system (B cells)

Question 1

what are the two types of adaptive defence systems and which are B cells more closely involved in

Answer 1

Humoral and Cellular defence
B cells are more involved with the Humoral system

Question 2

what is the name of the cell that both B cells and T cells differentiate from

Answer 2

Small Lymphocyte

Question 3

how long does the adaptive immune system usually take to respond

Answer 3

one to two weeks

Question 4

what is the basic protein structure of an antibody

Answer 4

IgG contais 2 heavy chains and two light chains

Question 5

explain how antibody diversity is generated in the genome

Answer 5

the light chain is encoded by one gene but at two different loci (kappa and lambda)
the heavy chain is encoded by one gene and a single locus
the VDJ recombination within these genes causes lots of diversity

Question 6

how many antibodies can VDJ recombination produce bye itself

Answer 6

2.09x10^6
(this still isn’t enough)

Question 7

what are the 3 structures that make up the antigen receptor of an antibody

Answer 7

CDR1, CDR2, CDR3 (sometimes called hyper variable loop (HV) 1,2 and 3).
the different arrangement of these 3 loops (caused by VDJ recombination) effect what anitigens they can bind to.

Question 8

what is somatic hypermutation

Answer 8

the VDJ segments of the genome are hypermutated to produce even more antibody diversity. This can increase an antibodies affinity for its antigen 1000 fold.

Question 9

what happens to B cells when developing in the bone marrow

Answer 9

They interact with stromal cells which are covered in self cell antigens. if a B cell recognises any of these then it will undergo apoptosis.

Question 10

what are required for a B cells BCRs to be activated

Answer 10

igA(alpha) and igB(beta) are accessory proteins required for the BCR to move to the cell surface
The B cells are then activated by Helper T cells which interact with the C40 receptor on the B cell.

Question 11

what happens to activated B cells that reach the lymph node

Answer 11

they move inside the germinal receptor in the node.
They undergo proliferation followed by somatic hypermutation.
next their affinity for the targeted antigen is assessed by dendrite cells, if they are not suitable they will apoptose.
finally, suitable B cells interact with T helper cells and undergo class switching, becoming either a plasma cell or B memory cell.

Question 12

what are the different types of antibodies

Answer 12

Monomers: IgD, IgE, IgG
Dimers: IgA
Pentamer: IgM

Question 13

how do antibodies stop pathogens

Answer 13

agglutination
neutralisation
histamines (mast cells)
compliment system
Opsonins